Colin Farmer, a retired architect who is 61 and cannot move unaided, was on his own and walking down a street in Chorley, in the county of Lancashire, on a Friday evening, when the incident happened.

“I heard this male voice shouting and bawling at me from behind and I became frightened because I thought I was about to be mugged,” he told reporters. “Obviously I am the perfect target for muggers, because I don't know what is going on around me and I carried on walking in the hope I would get away."

Farmer said that the next thing he knew was that he felt “this thump in the back, this huge electric shock” and it was like “thousands of volts going through his body”.

“I thought that I was honestly going to die and they were going to kill me. All my muscles turned to dust and I thought I was having another stroke. I said 'I'm blind, I'm blind. I'm blind,' but this policeman knelt on me and dragged my arms round my back.”

Only then did the policeman realize Farmer was not a criminal and promptly took him to hospital.

Lancashire police say they “deeply regret” putting Farmer through a “traumatic experience,” but say they made an honest mistake.

They say that the retiree’s walking stick matched the description of a samurai sword that had reportedly been wielded by a Chorley resident in the same area.

They also claim that Farmer’s behavior prompted the tasering.

“One of the officers who arrived in Chorley believed he had located the offender. Despite asking the man to stop, he failed to do so and the officer discharged his taser,” said Chief Superintendent Stuart Williams.

Farmer is not satisfied with the explanation.

“I walk at a snail's pace. They could have walked past me, driven past me in the van, or said drop your weapon – but as far as I'm concerned they didn't.”

The incident has been referred to Independent Police Complains Commission, which will conduct an investigation.

Meanwhile, Colin Farmer says that he is still unable to sleep or go outside without fear following the incident, and will not be satisfied until action is taken.

“I want this officer sacked, charged and locked up because there is no excuse whatsoever for attacking a registered blind and disabled retired man without warning and with such a potentially lethal weapon,” he said.

The real owner of the samurai sword, a “drunk and disorderly” 27-year-old man, was arrested later the same evening with no use of taser, and released without charge.

This is the second such incident this year, after officers tasered an agitated Alzheimer’s victim several times in May.

UK police recently asked for all front-line officers to be issued with tasers, rather than the current one-in-three.